A resilient and connected network of sites to sustain biodiversity under a changing climate

Significance In response to biodiversity loss, scientists have called for the protection of well-connected systems of protected areas covering 30 to 50% of the planet. However, as climate change drives shifts in species, conservation plans based on current biodiversity patterns will become less effective. We collaboratively develop and map a conservation network for the conterminous United States designed to represent all habitats, while anticipating and facilitating changes in species composition. The network is based on principles of representation, resilience, connectivity, and recognized biodiversity value, with each factor mapped in a way that anticipates climate change. The results are being used to inform land-acquisition and management decisions by The Nature Conservancy, many state and federal agencies, and hundreds of land trusts.

. Landscape diversity components and geophysical setting sources by region … p. 19   Table S1. Landscape diversity components and geophysical setting sources by region Data sources: USGS 30m Digital Elevation Data (1 arc-second) for elevation, slope, and topographically derived products such as Topographic Land Position -TPI (Fels 1995, Wilson andGallant 2000), Compound Topographic Index -CTI (Moore et al. 1993), Heat Load Index -HLI (McCune and Keon, 2002), and Landforms (Anderson et al. 2016

EASTERN REGION
To create a standardized metric of landscape diversity (LD) we transformed all three indices (landform variety (LV), elevation range (ER), and wetland density (WD) to standardized normal distributions ("Z-scores" with a mean of 0 and standard deviation of 1) then combined them into a single index. In the combined index, we weighted landform variety twice as much as the other two values because of the importance of this feature in creating well defined microclimates. Further, wetland density was only added when the setting was a flat landform (dry flat, wet flat, slope bottom flat). The final index was: Landscape Diversity on Flat Landforms = (2 LV + 1 ER + 1WD)/4 Landscape Diversity on Slopes = (2 LV + 1 ER)/3 Where LV = Landform Variety = (1*# Landforms) WD = Wetland Density = (2*Density in 0.41 ha) + 1* Density in 4.1 ha+ 1* #Wetland polygons in 0.41 ha) / 4 ER = Local Elevation Range = residual of elevation range in 0.41 ha circle regressed on LV

GREAT LAKES REGION
To create a final map of landscape diversity, we combined the landform variety score (LV) and the wetland influence score (WS) into a single index, using the transformed z-score values to ensure they were on the same scale. Landform variety was given twice the weight of wetland influence to reflect fundamental importance of microclimates to all types of terrestrial and wetland species. The wetland score was only added if the average combined value was higher with the wetland influence score than without it.

GREAT PLAINS REGION AND LOWER MISSISSIPPI REGION
To create a final score of landscape diversity, we combined the landform variety score and the wetland density score into a single index using the transformed Z-score values to ensure they were all data were on the same scale. For each cell, we used the maximum of the following two options as the final landscape diversity score: 1. Landform Variety Z Score 2. Landform Variety Z + Wetland Density Z) / 2 Where LV = Landform Variety = (1*# Landforms) WD = Wetland Density = (2*Density in 0.41 ha) + 1* Density in 4.1 ha) / 3 By using the maximum value, the wetland density was only incorporated in cells where it increased the base landform variety score.

ROCKY MOUNTAINS DESERT SOUTHWEST REGION
To create a final map of landscape diversity, we created a regional score within the 3 regions and an ecoregion score within each of the 12 ecoregions. For each cell, base score was the landform variety Z score within the given geography (region or ecoregion). The cell scores were then increased if they were identified by any of the boosting criteria for elevation, moisture, or wetland density. The boosts were limited to areas by comparing cell values to the landform variety score alone, and the magnitude of the boost varied depending on the magnitude of this difference. For example, to implement the wetland density boost, we subtracted the landform variety score from the wetland density score such that a positive difference indicated the wetland density was greater than the landform variety relative to their respective means. We then identified areas where wetland density was both 1) above the mean (>0.5 SD) and where 2) the difference between wetland density and landform variety was also above the mean (>0.5 SD) To these areas, we gave a slight boost (0.50 -2 SD) to the landscape diversity score scaling the boost to the size of the difference. See the full report for more details on each boost. Boosts varied between: 1. Elevation Range boost: 0.25-1 SD 2. Moist Landform boost: 0.25-1 SD 3. Wetland Density boost: 0.25-2 SD The final Landscape Diversity score was equal to landscape variety score plus the sum of the boosts. This was then divided by the standard deviation of the ecoregion to appropriately spread out the distribution and approximate standard normal units.

PACIFIC NORTHWEST REGION
In the Pacific Northwest: Landscape Diversity = (HLI index * CTI index) / STD (HLI index * CTI index). Where: HLI index = Heat Load Index range normalized 0-1, CTI index = Compound Topographic Index normalized 0-1 6. CALIFORNIA Landscape Diversity = ((HLI index*CTI index) + Maximum (HLI index, CTI index)). Where: HLI index = Heat Load Index range normalized 0-1, CTI index = Compound Topographic Index normalized 0-1    This map sums the priorities from 22 terrestrial and aquatic assessments from field staff and many partners. Values range from 1-12, indicating the number of plans that highlighted each pixel. We selected areas that scored 4 or above (i.e. were identified in four or more of the component maps  (2015): The Wildlife Action Network map, terrestrial components (Fig 1.3)

B. TNC Ecoregional Plan Sources
The Wildlife Action Network incorporates SGCN populations and sites with high SGCN richness, as well as viability. It serves three purposes: 1) addresses large-scale habitat stressors such as climate change, fragmentation, and invasive species; 2) increase the efficiency of actions by the conservation community; 3) prioritize and focus conservation through an additional step of identifying Conservation Focus Areas (a prioritization for the next 10 years  (2015): Map of terrestrial conservation opportunity areas (Fig. 6.6). Texas in in the process of revising their plan and has two types of assessments that were appropriate for this application, but only one was complete at the time of our compilation. We have incorporated an assessment a CHAT product, which incorporates SCGN distributions, but is primarily intended to identify sensitive resources and direct development away from them. This map draws information from an aggregated biodiversity value metric that is not yet complete for the state. The CHAT map uses these terrestrial maps as input, prioritizing areas that have confirmed presence and high-quality habitats. These "in progress" products were shared directly by the plan developers and are not in the current SWAP. A-C quality rare species locations and A-C quality community occurrences which which were not captured in the ecoregion or state based recognized biodiversity values. The analysis also included largest resilient patch of each geophysical setting if not already captured by the the ecoregion of state-based datasets, which restricted the actual additions to a few rare and underrepresented geophysical settings.  The secured areas dataset shows public and private lands that are permanently secured against conversion to development through fee ownership, easements, or permanent conservation restrictions. The dataset is a mix of federal, state, and local data sources compiled by a variety of agencies. The dataset and source for each polygon is available via the interactive map on the authoritative data page: https://tnc.maps.arcgis.com/home/item.html?id=e033e6bf6069459592903a04797b8b07

National Sources
Protected